An earlier question, How can I laminate with contact paper without leaving bubbles?, asked about covering books with adhesive contact paper, presumably to provide some protection. The image in the question was of clear adhesive plastic film sold for the purpose of protecting paper documents, books, etc. The specific example shown was a product called Transpaseal, which is described as:
Transpaseal book covering film. Self adhesive rolls of durable plastic film. Ideal for covering all types of books or design work.
There are other similar products, and one would assume that a product sold for the purpose of protecting books and paper documents would be designed to protect them. It ought to be possible to verify that the product is actually suitable for the purpose; e.g., the adhesive is non-acidic, and doesn't break down in long-term use, etc. Purchasers could check reviews to verify that a particular product didn't destroy other people's books or documents.
We can also assume a degree of common sense, like not gluing plastic film to an heirloom book, or one whose value depends on it being in mint condition.
An upvoted comment on the earlier question says that contact paper is a terrible method of book conservation.
If we stick to protecting non-rare books from the wear and tear of normal, regularly-occurring use, is it, in fact, a terrible method? Why? Does this apply to any and all cold adhesive lamination films, or could films of certain types/specifications be a good solution to protecting books? Would the material/construction of the book's cover make a difference in this advice?